This cable is primarily designed to establish serial connections between, for example, an HP retail system (point of sale/cash register environment) and peripheral devices that use a 9-pin RS-232/DB-9 interface. Examples include cash drawers, barcode scanners, magnetic stripe readers, etc., when the HP device uses an RJ-50 interface.
The K0A30AA cable is not a standard PC connection cable (e.g., not a USB cable, not a standard display cable) but is specifically designed for POS/serial/retail environments.